Wraparound Flap
The great toe wraparound was first described by Morrison and colleagues in 1980.1 It is used for one-stage reconstruction of soft-tissue loss of the thumb to provide coverage of exposed bone and tendon, with sensate tissue from the great toe. The flap includes the nail, skin, nerves, and subcutaneous vessels of the great toe.
Indications
This flap is indicated for coverage of acute and chronic thumb defects where the skin has been avulsed, resulting in a loss of the nail and soft tissues of the thumb, but where the flexor tendon and extensor tendon have been left behind.
It can be used for defects as small as from the thumb tip to the interphalangeal (IP) joint up to defects extending to just proximal to the metacarpophalangeal (MP) joint.
There are no time limits and no age restrictions, although it may not required as often in the pediatric population due to their superior wound-healing abilities.
Contraindications
The great toe wraparound flap cannot be used in patients with poor vascular flow to the toes and those patients without an appropriate recipient artery, vein, and nerve(s) in the hand.
Examination/Imaging
A preoperative evaluation with a pencil Doppler is performed to assess the patency of both digital arteries in the great toe.
Angiography is not necessary, but depending on the type of injury sustained by the patient, it may be valuable in the recipient hand.
Relevant Anatomy
The great toe wraparound flap is harvested from the foot ipsilateral to the hand injury. It derives its blood supply from the first dorsal metatarsal artery (FDMA) ( Fig. 50.1 ). The FDMA sprouts a common digital artery to the first web space dorsally. This common digital artery divides into great and second toe branches. The FDMA also sends a deep branch between the metatarsals to communicate with the medial plantar artery ( Fig. 50.2 ). The medial plantar artery also sprouts a common digital artery to the first web space ( Figs. 50.2 and 50.3 ). This common digital artery communicates with the great toe and second toe proper digital arteries. Either the dorsal common digital or the volar common digital may be dominant. Similarly, the FDMA or the medial plantar artery may be dominant. As a result, many anatomic variations of the blood supply to the great toe exist.
The venous drainage of the great toe is via the subcutaneous veins of the dorsal foot ( Fig. 50.1 ). Although the first dorsal metatarsal artery has venae comitantes, these are rarely used for outflow because of their small size.
The medial and lateral digital nerves to the great toe lie on the plantar aspect of the foot.
The wraparound flap is designed with the pulp of the toe, the nail, and the dorsal and lateral tissue ( Fig. 50.4 ). The skin and subcutaneous tissue are harvested, with some medial skin and the flexor and extensor tendons left behind.
Pitfalls/Complications
A disadvantage of this procedure is that it sacrifices a great toe when the proximal and distal phalanx of the toe are removed.
When the proximal and distal phalanx are kept, the healing of the skin-grafted donor site is slow. It may need a secondary flap to help in closure.
Skin-grafting the pedicle may be necessary to avoid tight closure over the vein or artery.
Adequate nerve length must be obtained at the donor area, or nerve grafting is necessary.